.page{
    max-width: 60em; /*body的默认字体是16px 16*60=960px*/
    border: 1px solid #ff1010;
}
.main{
    background-color: #000000;
    color: #ffffff;
    width: 62.5%;

    float: left;
}
.sideBar{
    background-color: #7e77ff;
    width: 31.25%;

    float: right;
}
.other-content{
    clear: both;
}
/*
媒体查询
仅当浏览器可视区域大于等于480px的时候把p元素的颜色设置为红色 字体粗体
*/
@media only screen and (min-width:
       480px) {
    p {
        color: red;
        font-weight: bold;
    }
    .other-content{
        color: red;
    }
}